1. Field of the Invention
The invention relates to a modular absorption measuring system for fluid media comprising a detection module and a sample module, wherein the detection module comprises a detection system, wherein the detection system comprises an electromagnetic radiation source and a quantum detector, wherein the sample module comprises a sample chamber, whereby the radiation source is designed to supply light in the direction of the sample chamber and the quantum detector is designed to receive light from the sample chamber.
2. Description of Related Art
Absorption measuring systems are preferably used in cases where a change in transparency can be used to determine the contents quantitatively. For example, the content of fines can be established in a liquid. Likewise absorption measuring systems are known, in which a sample material is filled into a sample chamber and the latter is evaluated afterwards in a measuring device. Likewise so-called measuring strips are known in which a test section and mostly also a reference section are used, wherein upon the contact of said sections with a sample liquid or in general with a physical/chemical sample a reaction occurs in the reaction section, which is revealed by a colour change or a change in the transparency of the reaction section.
In known devices the problem is also mostly that the sample device and the evaluation device have to be aligned very precisely relative to one another. Small inaccuracies in the alignment can lead to greater differences in the obtained result, which considerably worsens the quality and reliability of repeated measurements for example in a continuous monitoring task.
U.S. Pat. No. 6,995,348 B2 shows for example an optical detection system, in which a sample material in a channel is guided past a plurality of optical detection devices. Each optical detection device is formed in this case by a light source and a detector, which are arranged opposite one another, so that the emitted light passes through the channel and is detected on the opposite side by the detector. As the individual detection devices are arranged along a channel, the disclosed device is designed for example for determining a reaction along the channel. By arranging frequency selective filters in the beam path of each detection device however also an analysis of the sample is possible in different spectral ranges.
As the sample material in the channel passes through all detection devices a selective measurement is not possible for example with the use of a catalyst or an added reagent, as with such a measurement the sample is contaminated by the addition of the additive and thus an additional measurement in a different spectral range or with a different catalyst is usually not possible.
Document US 2007/0102654 A1 discloses an optical sensor, which comprises a detection module consisting of a light-emitting diode and a photodetector, made respectively from an organic semiconducting material. The emitted light passes through the sample holder and is detected by the photodiode. It is also disclosed that an economically attractive alternative to existing sensors is to be found, which is achieved in particular by an integrated structure. Integrated is understood to mean that the sensor is produced in one step, without parts or components of the sensor having to be produced separately, in order to be joined subsequently to the sensor. Both the OLED and the photodiode can be produced directly on a light conductor or a carrier material. The optical sensor comprises for measuring a reference signal a reference photodiode made from an organic semiconductor material, which reference signal originates from the OLED or a second light-emitting diode. Said reference diode is part of a reference module, which has an empty sample holder, in which no sample material is arranged, which sample holder however is passed through by the light of the same reference diode, which also irradiates the sample chamber and the detection photodiode. By means of a light conductor light is directed by the OLED via the sample holder to the photodiode and possibly in addition is directed via the empty sample holder. Furthermore, a non-transparent screen is provided, which should prevent light reaching the photodetector other than through the sample chamber and thus the falsification of the measurement results is prevented. Furthermore, the document discloses a method for producing an optical sensor, whereby an integrated arrangement of the photodiodes and the OLEDs is achieved, in that the latter are arranged on the detection module, whereby the detection module also comprises the sample holder.
Document EP 1 063 518 A2 discloses a device for analysing a gas sample by means of infrared absorption, in which on a common, thermally stabilised carrier, in the immediate vicinity of one another and on one side of the measuring cell, an emitter and a receiver are arranged, whereby the thermal drift of the emitter and the receiver is prevented. To analyse a gas sample by means of infrared absorption it is known that to achieve a measurement that is as precise as possible a long absorption line inside the measuring cell is advantageous. Furthermore, systematically caused fluctuations in the detection characteristics are to be avoided as far as possible. In addition, the emitter and the receiver are arranged on a common, thermally stabilised carrier in the immediate vicinity of one another and on one side of the measuring cuvette. The carrier is in this case a thermally stabilised metal element, on which for direct heating in addition a heating and a control element, for example a transistor, is arranged. Furthermore, an IR-component, for example an IR-photodiode, is provided in the immediate vicinity of the receiver. On the side of the measuring cell opposite the cell window there is a spherical mirror, in order to direct the radiation emitted by the emitter back to the photodiode. By means of direct heating it is possible to keep the carrier and thereby the emitter and the receiver constantly at a temperature of preferably about 55° C. and thus avoid thermally caused drift.
Furthermore, a light-emitting diode is known from the prior art, which has its maximum beam intensity in the region of 4.2 μm wavelength and thus can be used preferably for measuring the absorptions of CO2.